I'm finally looking at getting the summitt heads. They don't come with guide plates and they say machine work must be done to accodomate them. My question is what are the guide plates for and are they required. I was told these can be bolted on and ready to go. The motor is a 327, 67 camaro.

You'll want guide plates if you are running roller rockers. They are held in place under the hex-nut of the screw in rocker studs. They aid in keeping the pushrod in the proper alignment for the rocker. With stock stamped steel rockers the hole the pushrod goes through in the head is the guide. To use guide plates the hole has to be enlarged and the stud boss needs to be machined down for proper valve train alignment.

Thank you, I am using the stock rockers so no need for them.